I currently have over a dozen books published through Create Space.
Recently, I noticed they have not updated my sales reports.
The data for June is still up, when it used to be updated on the first of every month.
Besides that, they've stopped offering other services.

I am considering switching to Ingram/Spark, but wanted to know if anyone else has done this.
Wondering what to look out for, what the pros and cons are...

Being retired, on a fixed income, I have little disposable funds to shell out for book printing.
Should I be overly concerned?

Also, I'm unsure if I can transfer all of my titles to whichever company I pick...

If you own all the ISBNs, you can easily transfer the titles to IngramSpark. They have a process in place with CreateSpace to facilitate this move. You just need to contact IS customer support after setting up your account and explain what you want to do. They'll send you a form to fill out, and further instructions.

The setup fee is per book, but there is a promotion on at the moment to allow you free setup. I don't know what is off hand...SPARK...something or rather. Shouldn't be too hard to find it. Make sure you get your submissions correct the first time, because there is also a revision/re-submission fee.

The email stipulates "Free title setup on print or ebooks until July 31, 2018! Use Promo Code SPARKS." which means revisions are not included in this freebie. Bummer, I've got one title which I want to correct about 5 incorrect spellings of scientific names of plants. They are only incorrect in the Table of Contents, not on the pages where the plants are located - the spelling is correct on the actual pages where the plants are located. That means I only need to revise a single page - the TOC! Wonder how long I'll have to wait? Why didn't somebody point this out to me 10 days ago, I could have gotten it in for free. Such is life!

Wow. This puts a damper on things.
I know any funds output should be considered an investment
and not an expense, yet for someone on fixed income, it's hard to see it any other way.
Guess I'll have to keep saving my pennies.
Meantime, no major complaints on Createspace,
just wish things weren't moving so slowly.
Almost feels as if they're frozen in time.

Try contacting IngramSpark. I'm not sure they charge the title setup fee when you transfer titles to them from CreateSpace. They handle it all behind the scenes, so you don't actually have to set up anything other than your IS account. It wouldn't hurt to ask them if they charge the fee in such an instance. (I transferred all of mine in June when there was another discount code in effect, but I never had to enter it anywhere because, as I said, they handled it all behind the scenes.)

I moved all my titles from CS to IS. It went fairly smoothly. In my case I had to get new ISBN numbers and replace the copyright pages (because they had the old ISBNs). Because of the ISBN issue I did all the submissions through the IS interface instead of moving them directly from CS.

The setup went smoothly, the IS interface is very straightforward. I experienced no problems. Titles that were repeatedly suppressed for unknown reasons at CS didn't seem to cause any problems with IS (do they even have a validation team? If so, they don't have a hair trigger.)

I was delighted to see sales from a source I never expected: Espresso.

The only (very minor) thing I wish they would improve on is the ability to see all sales online like CS does. There is a choice to see sales online if you limit the report to one currency and one source, so I guess you can do it repeatedly to get all combinations. Seems silly. There is an email option where you can get everything sent, but they come in different batches.